Relating to methods for grinding rails

ABSTRACT

Method for grinding rails by means of a rail-borne vehicle, a frame movably supported on the vehicle, and at least one grinding unit adjustably mounted on the frame and arranged to provide at least one rail grinding zone. A rail follower is mounted on the frame substantially in line with the grinding zone, and the grinding unit is so supported that at least the grinding zone is adjustable transversely of the rail direction. At least one of the grinding zone and rail follower is locatable at different selected longitudinal spacings. The follower includes at least two points which contact the rail and by adjusting the grinding zone relative to the two point contact afforded by the follower, an optimum grinding position can be obtained dependent on the irregularities of the rail to be trued.

United States Patent Panetti June 10, 1975 [54] RELATING TO METHODS FORGRINDING 3,738,066 6/1973 51/178 RAILS FOREIGN PATENTS OR APPLICATIONSInventor: Romolo Pflnetli, e a, 1,231,751 4/1960 France 51/178Switzerland [731 Assignees: Speno International S.A., Geneva, PrimaryEmminef--lames 101165.

Switzerland; F k speno R il d Attorney, Agenl, 0r FirmWaters, Schwartz &Nissen Ballast Cleaning Co., Inc., lthaca, NY. [57] ABSTRACT [22] Filed:June 7, 1973 Method for grinding rails by means of a rail-borne ve- [ZI]Appl No 367 875 hicle, a frame movably supported on the vehicle, and atleast one grinding unit adjustably mounted on the frame and arranged toprovide at least one rail grind- [30] Foreign Application Priorlty Dataing zone. A rail follower is mounted on the frame sub- June a, 1972Switzerland 08498/72 stantially in lin ith the grinding zon and thegrinding unit is so supported that at least the grinding zone [52] US.Cl. 51/281 R; 51/178 is adjustable transversely of the rail direction.At least [51] Int. Cl B24b 1/00 one of the grinding zone and railfollower is locatable [58] Field of Search 51/281 R, 178 at difi'erentselected longitudinal spacings. The follower includes at least twopoints which contact the [56] References Cited rail and by adjusting thegrinding zone relative to the UNITED STATES PATENTS [W0 point contactafforded by the follower, an Optimum grinding position can be obtaineddependent on 13331333 351333 12??" "1111111?1111111111'111111111"51i541S the trregtttertttee ef the ttt be treet- 3,358,406 l2ll967 Speno et al5l/l73 8 Claims, 1 Drawing Figures 3,509,667 5/1970 Llndmark 5l/l78 I l,15 l 1s\ 26 31. r t n 1 1!. l

(,2 x 3 i e i A C A 7 1 1 g 1 -14 v t t 1 J PATENTEDJUH 10 ms SHEET Fig.3

Fig 2 1 RELATING TO METHODS FOR GRINDING RAILS BACKGROUND 1. Field ofthe Invention This invention relates to methods for grinding rails.

2. Prior Art It is known that with more concentrated and rapid traintraffic with increased axle loads. accelerated wear of the rail bearingsurfaces is caused, particularly on curves and in braking zones. Coldrolling. combined with the wearing away of metal particles, causesirregularities in the bearing surface of a rail. which tend to becomemore and more aggravated with continued use.

To eliminate this as quickly as possible, rotary grinders are used whichoperate either at their periphery (a substantially cylindrical workingsurface) or by an end face; in the latter case the grinder is usuallyformed with a central recess and may have one or two grinding zones.depending on its relationship to the rail.

It is of paramount importance not only to avoid accidental notches inthe rail. but also to obtain high precision. of the order of a fewhundredths of a millimeter.

For this purpose there have been proposed a number of variants of arigid frame fitted with a grinder fixed between wheels or slides formingrail tracers or followers. generally at the mid-point therebetween.Means for movement in the transverse direction of the frame make itpossible to adjust the grinder and the tracers relative to one another.The frame is then moved along the rail by various means. which ensuretransverse balance.

Machines of this type are adapted for truing the upper and/or innersurface of the rail head. Almost all these machines currently employ agrinder that can be inclined across the rail to adapt itself to thecurvilinear section of the bearing surface.

In high performance machines, several grinders are arranged along thesame frame, and they can all be adjusted transversely thereto. It thenbecomes possible to eliminate the tracers. as the grinders in sufficientnumber guide each other. In this category, there are machines in whichthe grinders on the same frame are able to slide transversely throughthe action of a fluid under pressure which apportions in different waysthe bearing force of each grinder against the rail. In this case thehydraulic or oleo-pneumatic association of the grinders also enables thetracers to be eliminated.

High performance machines as a rule have one or more of such frames perlength of rail. These are mov able in relation to the fixed frame of thevehicle that carries them so that they operate as stated. means(generally hydraulic) ensuring the necessary pressure for grinding and.at the end of the work. the lifting of the mobile frames.

The use of such frames, with single or multiple grinders with or withoutrail tracers, displays a common defeet which has often been noted: thepassage of the grinders leaves unaffected, or sometimes even causes,residual waviness along the bearing surface. which is incompatible withpresent railway requirements.

This fault is due to the fact that the distances between the points ofcontact of the grinders-or tracers correspond to the wavelength (orcertain fractions or multiples thereof) of the produced undulations. Thetools then tend to follow these undulations and even amplify themthrough the effect of resonance. In the known machines. the grinders ortracers are at fixed distances apart on the frame. and it is impossiblein operation to do away with this coincidence of periodicity.

Moreover, the use of sets of grinders of the type described comes upagainst additional difficulties owing to their length and the variablecurvature of the rail in the vertical and/or horizontal sense.

These two types of defect are also apparent when the grinders havedifferent transverse inclinations.

SUMMARY OF THE INVENTION An object of the present invention is to avoidthe serious drawbacks mentioned and to improve the precision andefficiency of high performance rail grinding machines.

According to one aspect of the present invention there is provided amethod of truing a rail by grinding. wherein the locus of a referencebase is defined by two point contact with the rail and grinding meansare adjustably mounted on the base to co-operate with the rail at atleast one grinding zone in line with said two points, and wherein thegrinding means are adjusted to shift at least said one grinding zonelongitudinally of the two point line to an optimum position dependent onthe irregularities of the rail to be trued.

For effecting the method of the present invention there is providedapparatus, comprising a frame to be carried by a rail-borne vehicle andmovable relative thereto, at least one grinding unit adjustably mountedon said frame and arranged to provide at least one rail grinding zone.and rail following means mounted on said frame and substantially in linewith said at least one grinding zone, at least one grinding zone beingadjustable transversely to the rail direction and at least one pair ofgrinding zones and rail following means being locatable at differentselected longitudinal spacings.

For a better understanding of the invention some constructional formsthereof will now be described. by way of example. with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a railgrinding machine according to the invention seen from outside the track;

FIG. 2 is an end view corresponding to a section on line I-I of FIG. 1;

FIG. 3 is a plan view corresponding to a section on line IIII of FIG. 1;

FIG. 4 is an explanatory diagram showing three grinders in side view;

FIG. 5 is a detail of a modification applicable to the machine of FIGS.1 to 4 and corresponds to part of FIG. 1;

FIG. 5a is a diagrammatic side view of another modification;

FIG. 6 is an end elevation transverse to the rail. showing anothergrinding machine truing the inner surface of the rail head;

FIG. 7 is a section taken on line VII-VII of FIG. 6', and

FIGS. 8, 9 and 10 are explanatory diagrams showing the working of threedifferent grinding machines.

DETAILED DESCRIPTION In FIGS. 1 to 3 there is seen a rail 1, which isassumed to be horizontal for ease of explanation. said rail supportingthe flanged wheels 2, 3 of a two-axle vehicle,

3 whose fixed frame is represented by a vertical plate 4. The plate 4 islocated directly above the rails and is in the shape of an inverted U tohold between its uprights a moving frame carrying grinding units.

This moving frame consists of a horizontal rectangular structure withtwo stringers 5,6, the stringer 5 being inside the rail whereas thestringer 6 is outside the rail. said stringers being welded tocross-pieces 7,8. The lat ter are centrally drilled and receive coaxialpivots 9 and 10, which are normally locked to the cross-pieces by screws1] and 12 respectively. These pivots include parts projecting outwardlyof the moving frame and formed as slides or shoes 13 and 14 which aregrooved at their ends. These grooves guide the frame for verticalmovement on the uprights of the plate 4, while preventing it fromrockingv Sufficient play is provided at the bottom of the grooves toallow a slight longitudinal slant of the movable frame structure.

Two vertical hydraulic jacks l5, 16 are pivotally connected at 17 and 18to the fixed frame 4 and at 19 and 20 to the slides 13 and 14respectively of the moving frame.

In this embodiment. three rotary grinders 21, 22 and 23 with verticalaxes are provided, each being fitted to a grinding unit of identicalconstruction. For simplicity of explanation only one grinder 22 will bedescribed.

The grinder 22 is mounted at the end ofa shaft 24 of a motor whosecasing 25 is extended by a tube 26 that houses the greater part of theshaft 24. This tube is provided with two transverse coaxial journals 27and 28 which respectively pivot in the middle of generally T- shapedplates 29 and 30 mounted transversely between the stringers S and 6.

Along the top of the inner stringer 5 there is formed a groove 31extending in the longitudinal direction and in which fits the roundedends of bolts 32 and 33 which pass through the corresponding upper innerflanges of the plates 29 and 30 respectively. The plates are alsocarried by the other stringer 6 through bolts 34 and 35 which passthrough the upper outer flanges, while the lower flanges of the platesare fitted with clamping bolts 36, 37, 38 and 39 arranged to engage theundersides of the stringers. The journals 27 and 28 can be locked bybolts 40 and 4!.

The operation of the grinding apparatus described is as follows:

The moving frame 5, 6, 7 and 8, guided by the uprights of the plate 4,is lowered by the jacks 15 and 16 to a desired horizontal positionindicated by scales 42, 43 on the uprights. Then each of the grindingunits is adjusted as described below for horizontal grinding of therail.

The four lower clamping bolts 36, 37, 38 and 39 are loosened. as are thelocking bolts 40 and 41 ofthe jour rials, while the grinding unit isheld upright. By rotating the guide bolts 32 and 33, and then thesupporting bolts 34 and 35, the plates 29 and 30 are brought in pairs tothe same level. The journals 27 and 28 which they support thus beinghorizontal, the undersurface of the grinder is parallel to a generatingline of the rail. Next, the motor is moved into exact vertical positionby pivoting on the journals 27 and 28, which are then locked by thebolts 40 and 4]. It will be seen that the plates 29 and 30 constitute asupport which, through the almost simultaneous operation of the fourbolts 32, 33, 34 and 35 makes it possible to adjust the undersurface ofthe grinder to be level with the rail. After this adjustment,

the four lower bolts 36, 37, 38 and 39 are clamped against the stringers5 and 6.

The three grinders are thus adjusted in turn. after which the motors arestarted and the jacks are actuated to apply the pressure required forgrinding as the vehicle is set in motion.

Since, in accordance with usual practice, these upright grinders arerecessed towards their center, it will be observed that the set of threerotary grinders produces six grinding zones spaced from one another inthe longitudinal direction of the frame, In this embodiment, these zonesare in the same plane. The passage of this grinding apparatus makes itpossible to eliminate slight irregularities due to wear of the bearingsurface of the rail, but in some circumstances more or less regularlongitudinal undulations of various wavelengths will remain aftergrinding, or will even be aggravated by the apparatus.

Consider first of all the simple case where, as illustrated in FIG. 1,the six contact zones on the rail are spaced regularly at a distancewhich coincides with the wavelength of an already existing corrugation,represented by broken lines in FIG. 1 with greatly exaggerateddifferences of level. It will be seen that the grinding apparatus willtend to follow this corrugation, especially since the length of thezones of effective grinding will be shorter than normal.

When, as illustrated diagrammatically in FIG. 4, the wavelength of acorrugation is twice the previous one, i.e. equal to the distancebetween the axes of adjacent grinders, for the most part only threealternate ones out of the six grinding zones will be in use at any onetime, which also accentuates the fault.

If, on the other hand, the corrugation found is shorter, experienceshows that a similar drawback can arise, albeit greatly attenuated bythe relative width of the grinding zones. lt nevertheless shows that theproblem of coincidence of periodicity can be maintained, or evenamplified, by the grinding apparatus itself. Other factors, such asgrinder wear, must be taken into account when setting up as they canaffect the performance.

With the apparatus described, a set of grinders can be readily adaptedto cope better with the conditions found in operation by modifying thespacing of the contact zones. To do this, it suffices to loosen the fourlower bolts 36, 37, 38 and 39 and move the grinder unit 22, for example,along the movable frame with its support plates guided by the bolts 32and 33 engaging in the longitudinal groove 31. It is possible to preventthe grinder from remaining in contact with the rail during this movementby slightly pivoting the unit on the rounded ends of the guide bolts 32,33.

The new position will be automatically correct, i.e. parallel to theprevious one, since none of the upper bolts of the support will havebeen turned. The lower bolts are then retightened.

From what has already been said, it should be clear that suchmodification of the spacing of the grinding zones can, by eliminatingthe coincidence of periodicity mentioned, do away with troublesomeresidual corrugations.

According to the conditions found, usually only a slight change in therelative positions of the grinders of a group will suffice for goodresults. At least one of the grinding units may therefore be infinitelyor continuously adjustable over a given length of the movable frame andmarks may be made on the frame to aid in positioning.

Nevertheless, observation of worn rails shows that. depending on thetype of construction of the track. certain categories of longitudinalcorrugations are frequently repeated. It is then possible and sufficientto provide discontinuous or stepwise adjustment along the frame for atleast one of the grinding units. For this purpose. the frame isprovided. after tests to determine what spacings are best, with detentmeans for at least one unit. These are shown as notches 44 in FIG. I andin a selected notch there is inserted the lower bolt 38 of theassociated unit. These detent means can. of course. be provided in manydifferent forms, for instance as projections on the stringer 6, or inthe form of a series of holes. They could also be provided on one of thesupport plates of the grinding unit. as shown in FIG. 5, where a pawlpivoted on the stringer 6 can engage in notches made in a plate 46screwed to the plate 29. The latter and the stringer could alternativelybe drilled to receive a removable peg inserted in two registering holes.These examples are of course by no means restrictive.

It may also be an advantage to be able to combine continuous, infiniteadjustment with intermittent stepwise adjustment. In the arrangement ofFIG. 5, the plate 46 has two elongated holes or slots through which itssecuring screws 47 extend. The plate 46 can be infinitely adjustedlongitudinally by the length of these slots by loosening the screws 47and retightening them after moving the plate. The coarse adjustment ismade in steps furnished by the notches of the plate 46, and the fineadjustment is made by sliding the plate 46 relative to the support plate29.

It is also possible selectively to couple grinders for simultaneouslongitudinal movement. In FIG. 5, a bar 47a is screwed to and connectsthe support plates 29 of the two end grinding units so that theirsimultaneous movement alters the distance between both pairs ofneighboring grinders. lt is still possible to move the end grindersseparately if the linking bar is removed and to secure them in theirindependent positions by their clamping bolts. The extremity of the bar470 has several holes for the screw to the plate 29 to pass through,which allows additional adjustment.

To assist truing, which is frequently done by passing to and fro alongthe same section of track, it is a particular advantage to distributethe grinders symmetrically in relation to the middle of the length ofthe frame. A single adjustment can then suffice, and marks may again beprovided on the frame by which to check the positions. FIG. 5a which isa diagrammatic detail of FIG. I, shows that for this purpose it isconvenient to use a rule 47)) graduated similarly in opposite directionsfrom its center. To avoid mistakes, there is provided anaid-to-positioning mechanism in the form of an endless cable 470traversing two pulleys 47d and 47e rotatably mounted at opposite ends ofthe stringer 6. The cable is provided with two indexes 47f. 47g thatco-operate with the rule and with which pointers on respective supportplates 29 are brought into registry. As the cable is moved. the indexesmove the same amount towards or away from the center. in a modification(not shown) the cable is fixed to the support plates at the re spectiveindex points so as positively to synchronize their movements.

It is possible. if necessary. to assist the longitudinal shifting of oneor more grinding units by known methods, such as rollers, jacks ormotors.

FIG. 6 shows, applied to one of the lateral faces of a rail 1, a grinder22' mounted at the end of a horizontal shaft 24' of a motor whose casing25' is extended by a tube 48 that houses most of the shaft. The middleof the tube 48 is expanded to form a piston 49 against which bears aspring 50. The piston 49 can slide in a cylinder 51 but is held againstrotation by a pin 52 engaging in a groove 53 of the tube. Fluid underpressure delivered by a pipe 54 to the chamber 55 opposite the springapplies the grinder against the rail with the pressure required forgrinding.

At the top of the cylinder 51 there is fixed a vertical pivot 56,lockable by a screw 57 to a horizontal arm 58. The latter is itselflockable in set angular positions by a screw or bolt 59 to the bottom ofa vertical shaft 60 provided with two diametrically opposite transversejournals 27' and 28'.

Three of these assemblies can be installed on the movable frame 5, 6, 7,and 8 and support plates 29 and 30 in place of as many rotary grinderswith vertical axes, their journals 27' and 28 taking the place of theprevious ones 27 and 28.

Setting up and operation are similar to the first described embodiment.

In FIG. 7, which is a horizontal section on the line I"- ll] of FIG. 6,one of the assemblies that has just been described is arranged fortruing the upper part of the rail bearing surface. The piston can belocked, for instance at the end of the stroke, by hydraulic pressure.

Operation is similar to that of the first embodiment, but the threegrinders only provide three zones of contact with the rail.

It will be noted that longitudinal adjustment of the contact zones canalso be obtained by appropriate rotations of the arm 58 and the casing25' of a grinding unit.

It will also be observed that these grinders with horizontal axes may,like the previous ones, incline across the frame, which can itself slopetransversely thanks to the pivots 9 and 10 of FIG. 1.

The grinding machines described furnish a further very importantadvantage: when an end grinder, for instance 21, is shifted, thedistance between the extreme contact zones is altered, which allows themachine to be readily adapted to the various curvatures of the rail.such as are found on curves and changes of incline, i.e. at places wheretruing is needed very often.

By correlating the total length between extreme zones to the distancebetween adjacent pairs of grinders, it is also possible to do away withundesirable residual corrugations.

in the case of very sharp bends of the rail, the end grinders areraised, or else they are inclined, as described above, which modifiesthe distribution of the possible contact zones along the frame.

On a straight track it is preferable, from the point of view ofprecision and speed of work, to true with more than three grinders perframe, this number not being restrictive. The grinders may be carried byvarious types of vehicle, and there may be two or more mobile framesmounted between or beyond the axles.

Referring back to FIG. 1, it it is assumed that the motor of one or eachextreme grinder has stopped, the latter would serve as a guide for thegrinders still in operation. However, if such guide means are required,the end grinders can be replaced by sliding shoes or rollers, formingrail tracers. It should be remembered that these tracers are subject toconsiderable wear owing to the abrasive powder used in grinding.

FIGS. 8 to are diagrams intended to show various modes of operation.

FIG. 8 illustrates a rotary grinder with a horizontal axis, acting inconjunction with two tracers, one leading, the other trailing, all beingmounted on a frame forming a reference base.

In the direction of travel, denoted by the arrow. the point A of contactof the leading tracer is on a rough section (greatly exaggerated in theillusration) of the rail, while point B of the rear tracer is on thepart already trued by the grinder, which is at zone 1A. it will be seenthat it is desirable to have the grinder set back along the base frametowards the rear tracer to lessen the influence of the roughnesses foundand to improve precision. Travel in the opposite direction would thenrequire the grinder to be shifted towards A.

If the distance between tracers is reduced, any local curvature will belittle effected by the grinding while if this distance is lengthened,grinding tends to eliminate the curvature.

For truing with alternating travel, the grinder is advantageously placedhalf-way between the tracers, which are themselves spaced to takeaccount of the irregularities to be trued.

FIG. 9 illustrates the case of a tracer guiding a grinder with avertical axis and therefore having two grinding zones, each supplyingthe other with a second tracing point. Again, the distance betweentracer and grinder is selected according to the conditions expected.

FIG. 10 shows a symmetrical distribution of grinders with vertical axes,it being possible to adjust the length between extreme grinders to thecurvature of the rail, and the distances between adjacent grinders tothe irregularities of the bearing surface.

It has been assumed above that the support(s) for the grinders ortracers was/were locked during grinding. It is also possible, however,to modify one or more of the longitudinal spacings as work progresses.For this purpose, the motor mentioned above as a possibility for movingthe grinding units may drive a device such as the cable of FIG. 5a, thecable being secured to one or more units. The clamping of the plates 29and 30 will not be absolute in that case.

It is also possible, by appropriate regulation, to govern speed oftravel in a particular manner, for instance it may be kept constant orbe made sinusoidally varying. Reciprocating movements, i.e. cyclicmovements, are particularly advantageous for improving the truingprecision.

It is emphasized that modification on the track of the longitudinalspacing of the grinders or tracers can be carried out when the grindersare rotating or are stationary; and either when the vehicle has stoppedor is in operation. It may be done before, after or during the operationof setting up the grinders at the correct level and angle.

What is claimed is:

l. A method of truing a rail by grinding comprising mounting a referencebase by two point contact with a rail to be ground, adjustably mountinga plurality of spaced grinders on the base to co-operate with the railat respective grinding zones in line with said two points, and adjustingthe longitudinal spacing between the grinders to shift said grindingzones longitudinally of the two point line to an optimum positiondependent on the irregularities of the rail to be trued.

2. A method as claimed in claim I comprising effecting grinding bypassing the grinder to and fro on the rail.

3. A method as claimed in claim 1, wherein the adjustment is made beforeeffecting a run with the grinders, and fixing the grinders at saidoptimum position.

4. A method as claimed in claim 1, wherein the adjustments are madeduring a run with the grinders on the rail in accordance with the shapeof the rail.

5. A method as claimed in claim 1, wherein adjustments are made during arun with the grinders on the rail as a function of time.

6. A method as claimed in claim 1, wherein adjustments are made inaccordance with a predetermined cycle.

7. A method as claimed in claim 1, wherein for curved rails, the twopoints of contact and said grind zone are spaced apart to provide amaximum spacing between endmost regions dependent on the curve.

8. A method as claimed in claim 1, wherein the grinding zones aremaintained symmetrically with respect to the mid-point between said twocontact points.

1. A method of truing a rail by grinding comprising mounting a referencebase by two point contact with a rail to be ground, adjustably mountinga plurality of spaced grinders on the base to co-operate with the railat respective grinding zones in line with said two points, and adjustingthe longitudinal spacing between the grinders to shift said grindingzones longitudinally of the two point line to an optimum positiondependent on the irregularities of the rail to be trued.
 2. A method asclaimed in claim 1 comprising effecting grinding by passing the grinderto and fro on the rail.
 3. A method as claimed in claim 1, wherein theadjustment is made before effecting a run with the grinders, and fixingthe grinders at said optimum position.
 4. A method as claimed in claim1, wherein the adjustments are made during a run with the grinders onthe rail in accordance with the shape of the rail.
 5. A method asclaimed in claim 1, wherein adjustments are made during a run with thegrinders on the rail as a function of time.
 6. A method as claimed inclaim 1, wherein adjustments are made in accordance with a predeterminedcycle.
 7. A method as claimed in claim 1, wherein for curved rails, thetwo points of contact and said grind zone are spaced apart to provide amaximum spacing between endmost regions dependent on the curve.
 8. Amethod as claimed in claim 1, wherein the grinding zones are maintainedsymmetrically with respect to the mid-point between said two contactpoints.